Danny Tetley has reportedly been struggling with illness ahead of his first live show.
The X Factor goes live for the first time in 2018 on Saturday but Danny's opening performance could be in jeopardy.
Insiders say he has been feeling ill and was even sent home from rehearsals in the week to get some rest.
"Danny had been rehearsing all week like the rest of the contestants, but he’s not been on top form," a source told the Daily Star newspaper. "He was so unwell on Wednesday that bosses decided it was for the best that he went home.
"Right now his main focus is getting better, but with the live shows kicking off on Saturday, everything is up in the air as to if he’s well enough to perform."
37-year-old Danny from Bradford is one of four finalists in the Overs category mentored by Ayda Williams. Joining him are Giovanni Spano, 33 from London, Janice Robinson, 50 from USA and Olatunji Yearwood, 32 from Trinidad and Tobago.
Speaking this week, Danny said: "I'm really excited! All those years of waiting have come down to this. I've dreamed of this and always wanted a chance to perform in the Live Shows. It didn't happen on Pop Idol and I've watched The X Factor for years and always wished it was me and now it finally is!
"I feel like I'm in the cast of High School Musical, everyone is non stop singing. It's full of constant noise and constant madness but good madness."
And he added of the reaction to him on the show: "It's been amazing. My niece looks after my social media for me and tells me all the lovely messages I get. Adam Lambert messaged me on Instagram saying he was backing me and Robbie mentioned me in his vlog so I've had an unbelievable reaction!"
The X Factor 2018 airs on ITV at Saturday 8:25PM and Sunday 8:00PM.